1. Field of the Invention
The present invention relates to a passively Q-switched laser.
2. Description of the Related Art
A conventional device comprises a solid-state laser medium disposed between a pair of reflective mirrors that constitute a resonator, a host crystal for absorbing the fluorescence generated from the solid-state laser medium in the resonator and increasing transmittance in accordance with the absorption, a semiconductor laser for emitting a laser beam that excites the solid-state laser medium, and a condensing optical system for condensing the laser beam emitted from the semiconductor laser onto the surface of the solid-state laser medium.
When the host crystal absorbs a laser beam from the semiconductor laser, the electron density of the excitation levels in the host crystal gradually increases, and because the excitation levels become filled at one point, the electron density is saturated, transparency is achieved, the Q-value of the resonance increases, and the passively Q-switched laser outputs a laser beam.
A conventional passively Q-switched laser is disclosed in Japanese Patent Application Laid-Open No. 2000-101175.